Aluminium oxide is impermeable and, unlike the oxide layers on many other metals, it adheres strongly to the parent metal. If damaged mechanically, aluminiumâs oxide layer repairs itself immediately.
Saliva helps remove oral waste and cavity-causing bacteria, protects teeth from decay by neutralizing harmful acids, and helps re-mineralize tooth enamel. Saliva also keeps oral tissues healthy by preventing infection by controlling bacteria and fungi in the mouth.
Problems can develop with the glands that produce saliva, including swelling, infection, cysts, tumours and salivary gland stones. Your salivary glands produce up to around 1.5 litres of saliva (spit) a day. It gets into the mouth through ducts or tubes called salivary ducts.